The present invention relates generally to an automated machining system and more particularly, to an automated machining system in which various machining operations can be simultaneously performed on one face of a plurality of work pieces which are carried on a pallet.
Transfer machining systems are known which are more or less permanently set up to simultaneously perform a succession of multiple, high-speed machining operations on large quantities of work pieces which are synchronously conveyed from station to station throughout the system. Upon completion of the longest work cycle of the different machining stations, all of the work pieces are transferred simultaneously to the next machining station. Because the work pieces cannot be transferred until the machining operations at each station have been completed, the work pieces remain at each machining station for a length of time equal to the longest work cycle of any of the machining stations.
Since all of the work cycles at each machining station are usually not equal, time is wasted at the other machining stations while the entire system waits for the longest work cycle to be completed. Thus, the time required for a work piece to travel through the entire transfer system is substantially greater than the actual machining and transfer time. Additionally, if there is a failure to load a work piece into the transfer system between transfer cycles, a gap in the production line will exist which decreases productivity and causes needless wear on the transfer mechanisms.
As a result, there is a need for machining systems which are more flexible yet also capable of mass production on a somewhat smaller scale than permanently set up transfer machines. The term flexible machining system is used herein to designate an automated machining system which has a high degree of flexibility with respect to changing or performing various machining operations on a variety of work pieces.
In a machining system of the present invention, a high degree of flexibility is provided by having each machining cell of each machining station equipped with a drive turret on the sides of which a plurality of different machine heads can be attached and having the work piece supporting pallets likewise supported on turrets which allow different surfaces of the work pieces mounted thereon to be presented for machining to the different machine heads. The machining system of the present invention includes a track having a pallet loading station and a pallet unloading station juxtaposed to the track, and at least one machining station juxtaposed to the track at a location between the loading and unloading stations. A plurality of pallets are supported for movement along the track between the unloading and loading stations and past the machining station. Each pallet is set up for mounting at least one work piece in a predetermined position thereon. The system also includes a series of mechanisms for moving the pallets along the track, a mechanism for locating and securing each pallet in a predetermined location at the machining station. Additionally, the system has a mechanism for sequentially rotating each pallet through a plurality of positions once it is located and secured at each machining station whereby different surfaces of the work pieces mounted thereon are selectively presented to tools on the machining station (e.g. drills, taps, etc.) for machining thereof and a mechanism at each machining station for producing relative movement between the pallet and the work station.
In operation, each pallet is brought into position with respect to one or more machining cells which are suitably programmed and set up to simultaneously perform a series of machining operations on one face of a plurality of work pieces mounted on the pallet. Upon completion of the machining operations on those faces, the entire pallet is partially rotated, thus presenting different faces of the work pieces to the machining cell for machining thereof. This sequence of machining the work pieces and stepwise rotation of the pallet is repeated until the front and vertical side faces of each work piece have been machined. If desired, the drive turret of the machining cell can then be rotated, presenting a different set of tools for machining the work pieces. The sequence of machining the work pieces and rotating the pallet is then repeated until the front and vertical side faces of each work piece have been machined for a second time. This sequence of drive turret rotation, machining and pallet rotation can be repeated until the work pieces have been machined as desired.
The object of this invention, generally stated is the provision of a flexible machining system which is particularly useful for accurately and rapidly machining work pieces.
An important object of the invention is the provision of such a flexible machining system which utilizes a track upon which a plurality of pallet carrying work pieces are slid between a loading and an unloading station, with at least one machining station therebetween, the pallets and machining stations being designed so that one side of three work pieces can be machined simultaneously.
Certain other objects of the invention will be obvious and others will be apparent to those skilled in the art from the following detailed description of a presently preferred embodiment of the invention taken in connection with the accompanying drawings wherein: